1. Field of the Invention
The present invention related generally to devices commonly referred to as lazy-tongs. More specifically, it relates to lazy-tong devices utilized to positively drive a scraper blade or other movable member away from a relatively fixed base member, and in particular to a unique bridge means for transferring power to both of the base leg means of a lazy-tongs arrangement from a hydraulic piston, so as to obtain even and positive forceful action from the arrangement.
2. Description of the Prior Art
A lazy-tongs device is made up of a plurality of legs of substantially equal length, arranged in crossed-over pairs that are pivoted scissors-like to each other centrally thereof, the outer ends of each crossed-over pair of legs being pivotally connected to the outer ends of the next pair. Such lazy-tongs devices have long been known, and provide a substantial degree of movement in an axial direction along the aligned scissor pivots, for a relatively small movement of the outer ends of the base legs of the lazy-tongs toward each other.
The lazy-tongs concept has many uses, one being to transmit power in an axial direction. There have been several arrangements proposed for this purpose, such as those shown in U.S. Pat. Nos. 1,984,766; 2,706,102; 3,032,319; and 3,228,659. While the lazy-tongs devices of each of these patents are effective for their intended purpose, in each case power is effectively applied to only one of the base legs of the device. This limits the amount of force that can be applied, and also places a large strain on the powered leg over the other leg of the lazy-tongs device.
The applicant has found that a lazy-tongs can be a more effective force transfer mechanism if both of the base leg means thereof have force applied thereto, and if the force is equally and simultaneously applied to the two base leg means. No arrangement for effectively doing such has heretofore been known, however. The applicant has devised a unique arrangement for evenly applying force simultaneously to both base leg means, while at the same time accommodating the converging movement of the base legs toward each other that occurs upon extension of the lazy-tongs. The present invention, therefore, is an improvement over previously known lazy-tongs devices utilized to transfer and apply force, and produces superior results over such conventional lazy-tongs devices.